This invention is concerned with optical signal processing. The availability of lasers, which provide a coherent light output, has made it feasible to use light for transmitting and receiving information. In a laser radar system, for example, laser light is directed toward a target. The portion of that light which is reflected from the target is processed and analyzed to provide information about the size, shape, and velocity of the target. Conventional laser radars, however, are subject to certain limitations in their performance. Heterodyne receivers, for example, are typically required to obtain an adequately amplified signal. In addition, space-based applications require large optical elements. The need for accurate scanning of the primary beam over many resolution spots introduces further complexitIes into the system. Conventional radar systems are also vulnerable to jamming.
This invention addresses these shortcomings in the laser radar systems of the prior art, and is applicable as well to a number of other optical signal processing applications.